Gas pressure regulator

ABSTRACT

A gas pressure regulator ( 10 ) is disclosed, comprising a body ( 12 ) fitted with a gas inlet stem ( 14 ), at a first end of the body ( 10 ), for receiving gas from a gas source at a first pressure, and a gas outlet stem or adaptor ( 16 ) at a second end of the body ( 10 ), for supplying gas at a desired pressure at the gas outlet stem ( 16 ). A pressure adjusting mechanism ( 18 ) is provided to enable a user to adjust and set the desired pressure, the pressure adjusting mechanism ( 18 ) comprising a movable piston arrangement ( 20 ). The gas pressure regulator ( 10 ) further comprises gas regulating means ( 22 ), to regulate gas flowing out of the gas outlet stem ( 16 ) to achieve the desired pressure set by the user. The gas regulating means ( 22 ) is securely fitted within the body ( 12 ) so as to be located within a gas flow path between the gas inlet stem ( 14 ) and the gas outlet stem ( 16 ), the gas regulating means ( 22 ) comprising an encapsulated valve ( 24 ) with a lever ( 26 ) that can be actuated by the movable piston arrangement ( 20 ) of the pressure adjusting mechanism ( 18 ).

FIELD OF THE INVENTION

The present invention relates to pressure regulators, and moreparticularly to gas pressure regulators for providing a substantiallycontinuous supply of gas at a substantially constant selected pressureto a gas outlet upon receiving pressurised gas from a gas source via agas inlet.

BACKGROUND TO THE INVENTION

Gas pressure regulators are well known, and typically aim to downregulate high pressure gas received from a gas source, such as a loosestanding gas cylinder, to a low pressure selected working gas pressure.Regulators typically comprise a gas inlet stem to receive the gas fromthe source, a regulating means to down regulate the inlet pressure tothe desired pressure, and a gas outlet stem to dispense the downregulated gas at the selected desired pressure.

The down regulating means typically comprises a combination of aselecting means for selecting and setting the threshold pressure, and arestricting means for preventing gas exceeding the desired pressure frompassing through the regulator from the gas inlet stem to the gas outletstem. The selecting means and the restricting means typically act inconcert in order to achieve the desired gas regulation. Typically, theselecting means includes an adjustable screw received through a housingof the gas regulator which in use actuates against a diaphragm locatedin an inside chamber of the housing allowing a user to adjust the volumeof the chamber. Gas entry from the gas inlet stem into the chamber iscontrolled via the restricting means, typically a poppet valve. In use,gas enters the inlet stem and enters the chamber via the poppet valve.Should the gas exceed the predetermined threshold the pressure of thegas will close the poppet valve, thus preventing further gas fromentering the chamber. The gas inside the chamber can exit through theoutlet stem and/or purge valves. As the pressure exerted by the gasinside the chamber drops, the poppet valve opens allowing more gas intothe chamber.

Gas regulators can be classified into single-stage and multi-stageregulators. Single stage regulators have a single chamber whereregulation of gas pressure takes place, in contrast to multi-stageregulators, which have two or more chambers where regulation of gaspressure takes place.

There are several problems associated with known gas pressureregulators. The diaphragm used in conventional gas regulators is highlyspecialized, both in regard to its design and material composition.Further, needle gauges used to measure the pressure at the gas inletand/or the gas outlet stems protrude from the regulator, making handlinguneasy, therein increasing the risk of unsafe handling practices.Further safety features, such as purge valve mechanisms, are oftenomitted from the designs. In addition, when a loose standing gascylinder accidentally topples over, the gas inlet stem can break loosefrom the gas cylinder, causing a potentially hazardous leak of highpressure gas.

There is thus a need to develop a safe, ergonomic and efficient gasregulator that at least partially ameliorates some of the abovementionedproblems.

SUMMARY OF THE INVENTION

According to a first aspect of the invention there is provided a gaspressure regulator comprising:

a body fitted with a gas inlet stem at a first end of the body, forreceiving gas from a gas source at a first pressure, and a gas outletstem or adaptor at a second end of the body, for supplying gas at adesired pressure at the gas outlet stem;

a pressure adjusting mechanism to enable a user to adjust and set thedesired pressure, the pressure adjusting mechanism comprising a movablepiston arrangement; and

gas regulating means to regulate gas flowing out of the gas outlet stemto achieve the desired pressure set by the user, the gas regulatingmeans being securely fitted within the body so as to be located within agas flow path between the gas inlet stem and the gas outlet stem, thegas regulating means comprising an encapsulated valve with a lever thatcan be actuated by the movable piston arrangement of the pressureadjusting mechanism.

In an embodiment, the body includes:

a first body component to which the gas inlet stem is fitted, the firstbody component defining an inlet chamber for receiving and accommodatinggas from the gas source via the gas inlet stem; and

a second body component to which the gas outlet stem is fitted, thesecond body component defining an outlet chamber for delivering gas tothe gas outlet stem,

the first and second body components being securingly fitted together soas to sealingly secure the encapsulated valve between the first andsecond body components, the encapsulated valve thus defining aninterface between the inlet and outlet chambers.

In an embodiment, gas pressure gauges are fitted to the first and secondbody components, and are arranged to measure and visibly display the gaspressure within each of the inlet and outlet chambers, respectively, soas to provide a measure of the gas pressure at the gas inlet and outletstems, which measure can be visually inspected.

In an embodiment, the encapsulated valve of the gas regulating meanscomprises:

a valve body having an inlet side and an outlet side, the lever beingpivotally fitted at the outlet side with a pivot pin, the lever havingan actuating cam proximate the pivot pin;

a capsule valve pin for abutting against the actuating cam of the lever,the valve pin further including a seat to sealingly engage a flowaperture defined in an inner wall within the valve body, the valve pinbeing movable between a default, closed position in which the lever isnot being actuated by the movable piston arrangement of the pressureadjusting mechanism and in which the seat seals against the flowaperture so as to prevent the flow of gas through the flow aperture, andan actuated, open position in which the lever is moved by the movablepiston arrangement of the pressure adjusting mechanism, with theactuating cam moving the valve pin so that the seat moves away from theflow aperture so as to allow the flow of gas through the flow aperture;and

biasing means to bias the valve pin towards the default, closedposition.

In an embodiment, a filter body is fitted to the inlet side of the valvebody, for filtering the gas flowing through the valve body.

In an embodiment, the pressure adjusting mechanism comprises:

a venting sleeve extending from a venting outlet defined in the secondbody component, the venting sleeve being in gas communication with theoutlet chamber of the second body component, the venting sleeve definingat least one venting aperture to enable gas to vent if/when required;

the piston arrangement incorporating a safety valve assembly, the pistonarrangement being housed partially within the venting sleeve andpartially within the venting outlet defined in the second bodycomponent, the piston arrangement comprising a guide flange beingsecured between the venting sleeve and the second body component, withthe piston arrangement being slidably movable relative to the guideflange between the open and closed positions; and

a pressure adjusting assembly that can be manually operated by a user toadjust and set the desired pressure, the pressure adjusting assemblycomprising a rotatable knob to actuate a movable spindle, which in turnactuates a biasing means within the venting sleeve, which in turnactuates the piston arrangement.

In an embodiment, the piston arrangement of the safety valve assemblycomprises:

a first piston body including a safety valve head, the safety valve headdefining at least one vent outlet, the first piston body including aninternal cavity to accommodate biasing means, the internal cavity beingin gas communication with the vent outlet to enable gas to escape fromthe first piston body; and

a second piston body extending from the first piston body, the secondpiston body being sealingly movable within the venting outlet defined inthe second body component to actuate the lever of the encapsulatedvalve, the second piston body defining a vent inlet and an adjacentinternal cavity that is in gas communication with the cavity of thefirst piston body,

wherein the piston arrangement, and the first piston body in particular,is slidably movable relative to the guide flange between the open andclosed positions.

In an embodiment, the second piston body includes the safety valveassembly, the safety valve assembly comprising a valve seat andassociated seat holder located within the internal cavity, with thebiasing means acting upon the seat holder and thus the valve seat toclose the vent inlet thereby preventing gas from entering the pistonarrangement. However, under sufficiently high pressures within theoutlet chamber, the valve seat is displaceable away from the vent inletto allow gas to flow through the vent inlet, through the internalcavities, and through the vent outlet so as to safely escape out of thegas pressure regulator.

In an embodiment, the pressure adjusting assembly comprises a body tothreadably accommodate a driving member, the rotatable knob being fittedto the driving member so as to threadably rotate and move the drivingmember through the body, the driving member having a central enlargedportion that is threaded to match the threading of the body and aterminal narrowed portion that is threaded to enable it to be threadablyaccommodated within the movable spindle, the movable spindle comprisinga sleeve to define an internal thread to match the threading provided onthe terminal narrowed portion of the driving member, the centralenlarged portion defining an internal circular recess to accommodate themovable spindle as the spindle threadably rotates relative to thedriving member.

In an embodiment, the movable spindle defines a pair of elongaterecesses on the outside surface of the spindle, with a pair of guidepins being fitted within the body to slidingly accommodate and guide thespindle as it moves relative to the body.

In an embodiment, the inlet stem comprises a first inlet stem memberfitted to the body, and in particular to the first body component, and asecond inlet stem member, which can be secured to the gas source, with afrangible zone of weakness being defined between the first and secondinlet stem members.

In an embodiment, the second inlet stem member comprises a sleeveincluding:

a frusto-conical filter which is secured in position with a retainer,the filter being positioned at a first end of the second inlet stemmember, proximate the gas source;

a valve spigot extending through an aperture defined at a second end ofthe second inlet stem member proximate the first inlet stem member, thevalve spigot including a seat to seat against the aperture so as toprevent the flow of gas therethrough; and

biasing means to bias the valve spigot into a closed position in whichgas is prevented from flowing through the aperture.

In an embodiment, the first inlet stem member, is fitted with a retaineragainst which the end of the valve spigot presses, so that when theinlet stem is intact, the retainer pushes the valve spigot away from theaperture, thereby allowing gas flow therethrough, but when the inletstem severs proximate the frangible zone of weakness, the biasing meanspushes the valve spigot so as to close the aperture, thereby preventingthe flow of gas from the gas source.

In an embodiment, the gas pressure regulator is fitted with protectivecladding to house the body. The cladding may comprise a pair of housinghalves that can be secured together with tamper proof screws.

In an embodiment, one of the cladding halves comprises a pair of visualinspection windows to enable a user to read the information on thepressure gauges, the inspection windows being substantially flush withthe cladding.

In an embodiment, the cladding defines a plurality of venting aperturesto enable gas leaving the venting sleeve, especially after the operationof the safety valve assembly, to escape to atmosphere.

According to a second aspect of the invention there is provided apressure adjusting mechanism for a gas pressure regulator, to enable auser to adjust and set the desired pressure, the pressure adjustingmechanism comprising:

a movable piston arrangement that can actuate a lever of a valve withinthe gas pressure regulator; and

a pressure adjusting assembly that can be manually operated by a user toadjust and set the desired pressure, the pressure adjusting assemblycomprising a rotatable knob to actuate a movable spindle, which in turnactuates first biasing means for actuating the piston arrangement.

In an embodiment, the pressure adjusting mechanism comprises a ventingsleeve that defines at least one venting aperture to enable gas to ventif/when required, the venting sleeve at least partially housing thepiston arrangement.

In an embodiment, the piston arrangement comprises:

a first piston body including a safety valve head, the safety valve headdefining at least one vent outlet, the first piston body including aninternal cavity to accommodate second biasing means, the internal cavitybeing in gas communication with the vent outlet to enable gas to escapefrom the first piston body; and

a second piston body extending from the first piston body, the first andsecond piston bodies being movable to actuate the lever of theencapsulated valve, the second piston body defining a vent inlet and anadjacent internal cavity that is in gas communication with the cavity ofthe first piston body.

In an embodiment, the second piston body includes a safety valveassembly, the safety valve assembly comprising a valve seat andassociated seat holder located within the internal cavity, with thesecond biasing means acting upon the seat holder and thus the valve seatto close the vent inlet thereby preventing gas from entering the pistonarrangement.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the invention may be better understood, embodiments of theinvention will be described below by way of example only and withreference to the accompanying drawings in which:

FIG. 1 shows an exploded perspective view of a gas pressure regulator inaccordance with the invention;

FIG. 2 shows the gas pressure regulator in FIG. 1 in an assembled form;

FIG. 3 shows a cross-sectional side view of the gas pressure regulatorin FIG. 2;

FIG. 4A shows a side view of the internal structure of the gas pressureregulator, with no cladding fitted;

FIG. 4B shows an end view of the gas pressure regulator in FIG. 4A;

FIG. 5A shows a perspective view of an encapsulated valve used withinthe gas pressure regulator, the valve being shown in a closed position;

FIG. 5B shows a cross-sectional side view of the encapsulated valve inFIG. 5A;

FIG. 5C shows a cross-sectional side view of the encapsulated valve inan open position;

FIG. 6A shows an exploded perspective view of a piston arrangement usedwithin the gas pressure regulator;

FIG. 6B shows a side view of the piston arrangement in FIG. 6A in anassembled form;

FIG. 6C shows a top view of the piston arrangement in FIG. 6A;

FIG. 7A shows a cross-sectional side view of the piston arrangement inFIGS. 6A and 6B, the piston arrangement being shown in a default closedposition;

FIG. 7B shows a cross-sectional side view of the piston arrangement inFIGS. 6A and 6B, the piston arrangement being shown in a venting, openposition;

FIG. 8 shows an exploded perspective view of a pressure adjustingassembly used within the gas pressure regulator;

FIG. 9A shows a side view of the pressure adjusting assembly in FIG. 8,assembled and in a raised, closed position;

FIG. 9B shows a cross-sectional side view of the pressure adjustingassembly in FIG. 9A;

FIG. 9C shows a side view of the pressure adjusting assembly in FIG. 8,assembled and in a lowered, open position;

FIG. 9D shows a cross-sectional side view of the pressure adjustingassembly in FIG. 9C;

FIG. 10A shows a cross-sectional side view of an inlet stem used inconjunction with the gas pressure regulator, the inlet stem comprising afirst inlet stem member and a second inlet stem member;

FIG. 10B shows a cross-sectional end view of the inlet stem in FIG. 10A,taken along line C-C in FIG. 10A;

FIG. 10C shows a cross-sectional side view of the second inlet stemmember after it snaps off the first inlet stem member;

FIG. 11 shows a cross-sectional side view of the gas pressure regulatorin a closed position;

FIG. 12 shows a cross-sectional side view of the gas pressure regulatorin a venting position;

FIG. 13 shows a cross-sectional side view of the gas pressure regulatorin a normal regulating position;

FIG. 14 shows a graph of the performance of a 1.5 bar pressure regulatorfor delivering acetylene, across a range of inlet pressures; and

FIG. 15 shows a graph of the performance of a 10 bar pressure regulatorfor delivering oxygen, across a range of inlet pressures.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring to FIGS. 1, 2, 3, 4A, 4B, 11, 12 and 13, a gas pressureregulator 10 comprises a body 12 fitted with a gas inlet stem 14 at afirst end of the body 10, for receiving gas from a gas source at afirst, high pressure. A gas outlet stem or adaptor 16 is fitted to asecond end of the body 12, for supplying gas at a desired, low pressurethrough the gas outlet stem 16.

The regulator 10 further comprises a pressure adjusting mechanism 18 toenable a user to adjust and set the desired pressure, the pressureadjusting mechanism 18 comprising a movable piston arrangement 20.

The regulator 10 further comprises gas regulating means 22 to regulategas flowing out of the gas outlet stem 16 to achieve the desiredpressure set by the user. The gas regulating means 22 is securely fittedwithin the body 12 so as to be located within a gas flow path betweenthe gas inlet stem 14 and the gas outlet stem 16. The gas regulatingmeans 22 comprises an encapsulated valve 24 with a lever 26 that can beactuated by the movable piston arrangement 20 of the pressure adjustingmechanism 18.

In an embodiment, the body 12 includes a first body component 28 towhich the gas inlet stem 14 is fitted, the first body component 28defining an inlet, high pressure chamber 30 for receiving andaccommodating gas from the gas source via the gas inlet stem 14. Thebody 12 further comprises a second body component 32 to which the gasoutlet stem 16 is fitted, the second body component 32 defining anoutlet, low pressure chamber 34 for delivering gas to the gas outletstem 16.

The first and second body components 28, 32 are securingly fittedtogether with screws 36 so as to sealingly secure the encapsulated valve24 between the first and second body components 28, 32, the encapsulatedvalve 24 thus defining an interface between the inlet, high pressure andoutlet, low pressure chambers 30, 34.

In an embodiment, gas pressure gauges 38, 40 are fitted to the first andsecond body components 28, 32 with screws 41, and are arranged tomeasure and visibly display the gas pressure within each of the inletand outlet chambers 30, 34, respectively. This provides a measure of thegas pressure at the gas inlet and outlet stems 14, 16, which measure canbe visually inspected.

Turning now to FIGS. 5A, 5B and 5C, the encapsulated valve 24 of the gasregulating means 22 comprises a valve body 50 having an inlet side 52and an outlet side 54. The lever 26 is pivotally fitted at the outletside 54 with a pivot pin 56, the lever 26 being positioned between twospaced apart walls 58, 60. A cylindrical wall 62, from which the spacedapart walls 58, 60 extend, defines a plurality of apertures 64 forallowing gas to exit the valve body 50 (as shown by the arrows in FIG.5C). The lever 26 has an actuating cam 66 proximate the pivot pin 56.

The encapsulated valve 24 further comprises a capsule valve pin 68,terminating at one end with a friction cap 70, for abutting against theactuating cam 66 of the lever 26. The valve pin 68 further includes aseat 72 (and associated seat holder 74) to sealingly engage a flowaperture 76 defined in an inner wall 78 within the valve body 50. Thevalve pin 68 is movable between a default, closed position (shown inFIGS. 5A and 5B) and an actuated, open position (shown in FIG. 5C).

In the default, closed position, the lever 26 is not actuated by themovable piston arrangement 20 of the pressure adjusting mechanism 18.The seat 72 thus seals against the flow aperture 76 so as to prevent theflow of gas through the flow aperture 76.

In the actuated, open position, the lever 26 is moved by the movablepiston arrangement 20 of the pressure adjusting mechanism 18, with theactuating cam 66 accordingly moving the valve pin 68 so that the seat 72moves away from the flow aperture 76 so as to allow the flow of gasthrough the flow aperture 76.

A holder 80 is provided to accommodate the seat 72 of the valve pin 68;in particular, the holder 80 securely holds the seat holder 74.

The encapsulated valve 24 further comprises a guide 82 to define achannel 84 for slidingly accommodating the holder 80, and to control themovement of the valve pin 68 between the open and closed positions.Biasing means 86, in the form of a spring, biases the valve pin 68towards the default, closed position.

In an embodiment, a conical filter body 88 is fitted to the inlet side52 of the valve body 50, for filtering the gas flowing through the valvebody 50, with the filter body 88 housing the guide 82 and the biasingmeans 86.

In an embodiment, the body 50 of the encapsulated valve 24 defines acircular flange 90, which gets sandwiched between complementary steppedformations defined in the first and second body components 28, 32, asindicated by circled zones 92 and 94 in FIG. 11.

Referring back to FIGS. 1, 2, 3, 4A, 4B, 11, 12 and 13, the pressureadjusting mechanism 18 comprises a venting sleeve 100 extending from aventing outlet 102 defined in the second body component 32. The ventingsleeve 100 is in gas communication with the outlet chamber 34 of thesecond body component 32. The venting sleeve 100 defines at least oneventing aperture 104, but typically two, to enable gas to vent if/whenrequired.

With reference now also to FIGS. 6A, 6B, 6C, 7A and 7B, the pistonarrangement 20 incorporates a safety valve assembly 106, which will bedescribed further below. The piston arrangement 20 is housed partiallywithin the venting sleeve 100 and partially within the venting outlet102 defined in the second body component 32. The piston arrangement 20comprises a guide flange 108 which is secured in place, typically bybeing sandwiched between the venting sleeve 100 and the second bodycomponent 32. The piston arrangement 20 is thus slidably movablerelative to the guide flange 108 between the open and closed positions,so as to actuate or not actuate the lever 26, respectively.

The pressure adjusting mechanism 18 further comprises a pressureadjusting assembly 110 that can be manually operated by a user to adjustand set the desired pressure. The pressure adjusting assembly 110 inturn comprises a rotatable knob 112 to actuate a movable spindle 114(shown in FIGS. 9B, 9C and 9D), which in turn actuates a biasing means116, in the form of a spring, via an intermediate spring plate 118,within the venting sleeve 100, which in turn actuates the pistonarrangement 20.

Turning back to FIGS. 6A, 6B, 6C, 7A and 7B, the piston arrangement 20comprises a first piston body 150 including a safety valve head 152. Thesafety valve head 152 defines at least one vent outlet 154, with thefirst piston body 150 including an internal cavity 156 to accommodatebiasing means 158, in the form of a spring. The internal cavity 156 isin gas communication with the vent outlet 154 to enable gas to escapefrom the first piston body 150.

The piston arrangement 20 further comprises a second piston body 160extending from (and typically fixed to) the first piston body 150. Thefirst and second piston bodies 150, 160 move in concert relative to theguide flange 108, with the second piston body 160 being sealinglymovable within the venting outlet 102 defined in the second bodycomponent 32. An O-ring 162 is located within a peripheral recess 164 tomaintain this seal. The O-ring 162 effectively replaces the function ofthe diaphragm in known gas pressure regulators, and its robust structureand operation is ideally suited for this.

The second piston body 160 terminates in a friction pin 166 to actuatethe lever 26 of the encapsulated valve 24. The second piston body 160defines a vent inlet 168 and an adjacent internal cavity 170 that is ingas communication with the cavity 156 of the first piston body 150.

Thus, in use, the piston arrangement 20, and the first and second pistonbodies 150, 160 in particular, are slidably movable relative to theguide flange 108 between the open and closed positions (to actuate ornot actuate the lever 26, respectively).

In an embodiment, the second piston body 160 includes the safety valveassembly 106, the safety valve assembly 106 comprising a valve seat 172and associated seat holder 174 located within the internal cavity 170.The biasing means 158 is arranged to act upon the seat holder 174, andthus the valve seat 172, to close the vent inlet 168, thereby preventinggas from entering the piston arrangement 20 (under closed and normaloperating conditions, with reference to FIGS. 11 and 13, respectively).However, under sufficiently high pressures within the outlet chamber 34,with reference to FIG. 12, the piston assembly is pushed upwardly (i.e.the first and second piston bodies 150, 160 move up relative to theguide flange 108, against the bias of the spring 116) and the valve seat172 is displaced away from the vent inlet 168 (against the bias of thespring 158) to allow gas to flow through the vent inlet 168, through theinternal cavities 156, 170, and through the vent outlet 154 so as tosafely escape out of the gas pressure regulator 10, as shown by arrows176.

Turning now to FIGS. 8, 9A, 9B, 9C and 9D in more detail, the pressureadjusting assembly 110 comprises a body 200 to threadably accommodate adriving member 202. The rotatable knob 112 is fitted to the drivingmember 202 so as to threadably rotate and move the driving member 202through the body 200. The driving member 202 has a central enlargedportion 204 that is threaded to match the threading 206 of the body 200,and a terminal narrowed portion 208 that is threaded 210 to enable it tobe threadably accommodated within the movable spindle 114. The movablespindle 114 comprises a sleeve to define an internal thread 212 to matchthe threading 210 provided on the terminal narrowed portion 208 of thedriving member 202. The central enlarged portion 204 defines an internalcircular recess 214 to accommodate the movable spindle 114 as thespindle 114 threadably rotates relative to the driving member 202.

In an embodiment, the movable spindle 114 defines a pair of elongaterecesses 216, 218 on the outside surface of the spindle 114, with a pairof guide pins 220, 222 being fitted within the body 200 to slidinglyaccommodate and guide the spindle 114 as it moves relative to the body200.

A pin retainer plate 224 is provided to secure the guide pins 220, 222in place within the body 200. The rotatable knob 112 is fitted to thedriving member 202 via torque plate 226 that is secured in place bymeans of a nut 228 secured to the driving member. A tamper proof knobcap 230 is fitted to the knob 112.

This double threaded arrangement (i.e. the thread on portion 204engaging the thread 206 and the thread 210 engaging the thread 212) ofthe pressure adjusting assembly 110 allows a relatively greaterdisplacement of the spindle 114, with relatively fewer turns. In anembodiment, the maximum open setting may be achieved in just two turnsof the knob 112.

Turning now to FIGS. 10A, 10B and 100, the inlet stem 14 comprises afirst inlet stem member 250, which is fitted to the first body component28. A stem nut 252, as shown in FIG. 1, for example, is carried on theinlet stem 14 to facilitate securement to the gas source. The inlet stem14 further comprises a second inlet stem member 254, which can besecured to the gas source, with a frangible zone of weakness 256 beingdefined between the first and second inlet stem members 250, 254.

In an embodiment, the second inlet stem member 254 comprises a sleeve257 including a frusto-conical filter 258, which is secured in positionwith a retainer 260. The filter 258 is positioned at a first end 262 ofthe second inlet stem member 254, proximate the gas source. A valvespigot 264 extends through an aperture 266 defined at a second end 268of the second inlet stem member 254 proximate the first inlet stemmember 250, the valve spigot 264 including a seat 270 to seat againstthe aperture 266 so as to prevent the flow of gas therethrough. Biasingmeans 272, in the form of a spring, is provided to bias the valve spigot264 into a closed position in which gas is prevented from flowingthrough the aperture 266.

In an embodiment, the first inlet stem member 250, is fitted with aretainer 274 against which the end of the valve spigot 264 presses, sothat when the inlet stem 14 is intact, the retainer 274 pushes the valvespigot 264 away from the aperture 266, thereby allowing gas flowtherethrough. However, when the inlet stem (250) severs proximate thefrangible zone of weakness (256), the biasing means 272 pushes the valvespigot 264 so as to close the aperture 266, thereby preventing the flowof gas from the gas source.

As best shown in FIG. 1, the gas pressure regulator 10 is fitted withprotective cladding 300 to house the body 12. The cladding 300 comprisesa pair of housing halves 302, 304 that can be secured together withtamper proof screws 306, the cladding 300 being fabricated from impactresistant and fire retardant material (e.g. nylon), which is splash anddust resistant, light and low maintenance.

One of the cladding halves comprises a pair of visual inspection windows308 to enable a user to read the information on the pressure gauges 38,40, the inspection windows 308 being substantially flush with thecladding 300. This ensures a slim design, thus preventing accidentaldamage to the gauges 38, 40.

In an embodiment, the cladding 300 defines a plurality of ventingapertures 310 to enable gas to leave the venting sleeve 100, especiallyafter the operation of the safety valve assembly 106, to escape toatmosphere.

The illustrated version shows a side inlet entry version of theregulator 10. However, in an alternate version, a bottom inlet entryversion is possible, and to achieve both possibilities, the first bodycomponent 28 defines two inlet opening 312, 314. The cladding 300,accordingly, defines two apertures 316, 318. Thus, in the illustratedside inlet entry version, in which the inlet stem 14 is secured to theopening 312, the aperture 318 in the cladding is fitted with a plug 320.Conversely, in the bottom inlet entry version, a similar plug would beused to plug the aperture 316 in the cladding 300.

Thus, when not in use (i.e. when closed, as shown in FIG. 11), the lever26 is not actuated, and thus the encapsulated valve 24 is closed,thereby preventing the flow of gas through the regulator 10. However,during normal use, as shown in FIG. 13, in which a user rotates the knob112 so as to move the spindle 114 downwardly, and thus the pistonarrangement 20 downwardly as well, so as to actuate the lever 26, thisopens the encapsulated valve 24 so as to allow the flow of gastherethrough. Thus, incoming high pressure gas enters the inlet stem 14(as shown by arrow 340) with low pressure gas then exiting the outletstem/adaptor 16 (as shown by arrow 342). However, during an emergency,as shown in FIG. 12, in which gas needs to vent rapidly out of theregulator 10, the valve seat 172 is forced to move away from the ventinlet 168, thus allowing gas to enter the piston arrangement 20 and thenescape out of the regulator 10 via the venting sleeve 100.

Finally, FIG. 14 shows a graph 350 of the performance of the 1.5 barpressure regulator for delivering acetylene, in which 352 shows theperformance of the regulator at 25 bar, 354 at 15 bar, and 356 at 4 bar.

Similarly, FIG. 15 shows a graph 360 of the performance of the 10 barpressure regulator for delivering oxygen, in which 362 shows theperformance of the regulator at 200 bar, 364 at 100 bar, 366 at 50 barand 368 at 21 bar.

The present invention clearly has a number of advantageous features, butin general terms, the interaction between the inlet and outlet chambersand the piston arrangement and encapsulated valve enables the pressureto be regulated in stages, thereby minimizing pressure fluctuations soas to mimic a multi-stage regulator.

1-27. (canceled)
 28. A gas pressure regulator, comprising: a body fittedwith a gas inlet stem, at a first end of the body, for receiving gasfrom a gas source at a first pressure, and a gas outlet stem or adaptorat a second end of the body, for supplying gas at a desired pressure atthe gas outlet stem; a pressure adjusting mechanism to enable a user toadjust and set the desired pressure, the pressure adjusting mechanismcomprising a movable piston arrangement; and gas regulating means, toregulate gas flowing out of the gas outlet stem to achieve the desiredpressure set by the user, wherein the gas regulating means is securelyfitted within the body so as to be located within a gas flow pathbetween the gas inlet stem and the gas outlet stem, the gas regulatingmeans comprising an encapsulated valve with a lever that can be actuatedby the movable piston arrangement of the pressure adjusting mechanism.29. The gas pressure regulator of claim 28, wherein the body includes: afirst body component, to which the gas inlet stem, is fitted, the firstbody component defining an inlet chamber for receiving and accommodatinggas from the gas source via the gas inlet stem; and a second bodycomponent, to which the gas outlet stem is fitted, the second bodycomponent defining an outlet chamber for delivering gas to the gasoutlet stem, the first and second body components being securinglyfitted together so as to sealingly secure the encapsulated valve betweenthe first and second body components, the encapsulated valve thusdefining an interface between the inlet and outlet chambers.
 30. The gaspressure regulator of claim 28, wherein gas pressure gauges are fittedto the first and second body components, and are arranged to measure anddisplay the gas pressure within each of the inlet and outlet chambers,respectively, so as to provide a measure of the gas pressure at the gasinlet and outlet stems.
 31. The gas pressure regulator of claim 28,wherein the encapsulated valve of the gas regulating means, comprises: avalve body having an inlet side and an outlet side, the lever beingpivotally fitted at the outlet side with a pivot pin, the lever havingan actuating cam, proximate the pivot pin; a capsule valve pin forabutting against the actuating cam of the lever, the valve pin furtherincluding a seat to sealingly engage a flow aperture defined in an innerwall within the valve body, the valve pin being movable between adefault, closed position in which the lever is not actuated by themovable piston arrangement of the pressure adjusting mechanism and inwhich the seat seals against the flow aperture, so as to prevent theflow of gas through the flow aperture, and an actuated, open position inwhich the lever is moved by the movable piston arrangement of thepressure adjusting mechanism, with the actuating cam moving the valvepin so that the seat moves away from the flow aperture so as to allowthe flow of gas through the flow aperture; and first biasing means tobias the valve pin towards the default, closed position.
 32. The gaspressure regulator of claim 31, wherein a filter body is fitted to theinlet side of the valve body for filtering the gas flowing through thevalve body.
 33. The gas pressure regulator of claim 29, wherein thepressure adjusting mechanism comprises: a venting sleeve extending froma venting outlet defined in the second body component, the ventingsleeve being in gas communication with the outlet chamber of the secondbody component, the venting sleeve defining at least one ventingaperture to enable gas to vent if/when required; the piston arrangementincorporating a safety valve assembly, the piston arrangement beinghoused partially within the venting sleeve and partially within theventing outlet defined in the second body component, the pistonarrangement comprising a guide flange secured between the venting sleeveand the second body component, with the piston arrangement beingslidably movable relative to the guide flange between the open andclosed positions; and a pressure adjusting assembly that can be manuallyoperated by a user to adjust and set the desired pressure, the pressureadjusting assembly comprising a rotatable knob to actuate a movablespindle, which in turn actuates second biasing means within the ventingsleeve, which in turn actuates the piston arrangement.
 34. The gaspressure regulator of claim 33, wherein the piston arrangementcomprises: a first piston body including a safety valve head, the safetyvalve head defining at least one vent outlet, the first piston bodyincluding an internal cavity to accommodate third biasing means, theinternal cavity being in gas communication with the vent outlet toenable gas to escape from the first piston body; and a second pistonbody extending from the first piston body, the second piston body beingsealingly movable within the venting outlet defined in the second bodycomponent to actuate the lever of the encapsulated valve, the secondpiston body defining a vent inlet and an adjacent internal cavity thatis in gas communication with the cavity of the first piston body,wherein the piston arrangement, and the first piston body in particular,is slidably movable relative to the guide flange between the open andclosed positions.
 35. The gas pressure regulator of claim 34, whereinthe second piston body includes the safety valve assembly, the safetyvalve assembly comprising a valve seat and associated seat holderlocated within the internal cavity, with the third biasing means actingupon the seat holder and thus the valve seat to close the vent inletthereby preventing gas from entering the piston arrangement, so thatunder sufficiently high pressures within the outlet chamber, the valveseat is displaceable away from the vent inlet to allow gas to flowthrough the vent inlet, through the internal cavities, and through thevent outlet so as to safely escape out of the gas pressure regulator.36. The gas pressure regulator of claim 33, wherein the pressureadjusting assembly comprises a body to threadably accommodate a drivingmember, the rotatable knob being fitted to the driving member so as tothreadably rotate and move the driving member through the body, themovable spindle defining a pair of elongate recesses on the outsidesurface of the spindle, with a pair of guide pins being fitted withinthe body to slidingly accommodate and guide the spindle as it movesrelative to the body.
 37. The gas pressure regulator of claim 36,wherein the driving member includes a central enlarged portion that isthreaded to match the threading of the body and a terminal narrowedportion that is threaded to enable it to be threadably accommodatedwithin the movable spindle, the movable spindle comprising a sleeve todefine an internal thread to match the threading provided on theterminal narrowed portion of the driving member, the central enlargedportion defining an internal circular recess to accommodate the movablespindle as the spindle threadably rotates relative to the drivingmember.
 38. The gas pressure regulator of claim 28, wherein the inletstem comprises a first inlet stem member fitted to the body, and asecond inlet stem member, which can be secured to the gas source, with afrangible zone of weakness being defined between the first and secondinlet stem members.
 39. The gas pressure regulator of claim 38, whereinthe second inlet stem member comprises a sleeve including: afrusto-conical filter which is secured in position with a retainer, thefilter being positioned at a first end of the second inlet stem member,proximate the gas source; a valve spigot extending through an aperturedefined at a second end of the second inlet stem member proximate thefirst inlet stem member, the valve spigot including a seat to seatagainst the aperture so as to prevent the flow of gas therethrough; andfourth biasing means to bias the valve spigot into a closed position inwhich gas is prevented from flowing through the aperture.
 40. The gaspressure regulator of claim 39, wherein the first inlet stem member isfitted with a retainer against which the end of the valve spigotpresses, so that when the inlet stem is intact, the retainer pushes thevalve spigot away from the aperture, thereby allowing gas flowtherethrough, and when the inlet stem severs proximate the frangiblezone of weakness, the fourth biasing means pushes the valve spigot so asto close the aperture, thereby preventing the flow of gas from the gassource.
 41. The gas pressure regulator of claim 28, wherein the gaspressure regulator is fitted with protective cladding to house the body,the cladding comprising a pair of housing halves that can be securedtogether with fixing means, with one of the cladding halves comprisingat least one visual inspection windows that is substantially flush withthe cladding, the cladding defining a plurality of venting apertures toenable gas to vent to atmosphere.
 42. A pressure adjusting mechanism fora gas pressure regulator, to enable a user to adjust and set the desiredpressure, wherein the pressure adjusting mechanism comprises: a movablepiston arrangement that can actuate a lever of a valve within the gaspressure regulator; and a pressure adjusting assembly that can bemanually operated by a user to adjust and set the desired pressure, thepressure adjusting assembly comprising a rotatable knob to actuate amovable spindle, which in turn actuates first biasing means foractuating the piston arrangement.
 43. The pressure adjusting mechanismof claim 42, wherein the pressure adjusting mechanism comprises aventing sleeve that defines at least one venting aperture to enable gasto vent if/when required, the venting sleeve at least partially housingthe piston arrangement.
 44. The pressure adjusting mechanism of claim43, wherein the piston arrangement comprises: a first piston bodyincluding a safety valve head, the safety valve head defining at leastone vent outlet, the first piston body including an internal cavity toaccommodate second biasing means, the internal cavity being in gascommunication with the vent outlet to enable gas to escape from thefirst piston body; and a second piston body extending from the firstpiston body, the first and second piston bodies being movable to actuatethe lever of the encapsulated valve, the second piston body defining avent inlet and an adjacent internal cavity that is in gas communicationwith the cavity of the first piston body.
 45. The pressure adjustingmechanism of claim 44, wherein the second piston body includes a safetyvalve assembly, the safety valve assembly comprising a valve seat andassociated seat holder located within the internal cavity, with thesecond biasing means acting upon the seat holder and thus the valve seatto close the vent inlet thereby preventing gas from entering the pistonarrangement, so that under sufficiently high pressures within the gaspressure regulator, the valve seat is displaceable away from the ventinlet to allow gas to flow through the vent inlet, through the internalcavities, and through the vent outlet so as to safely escape out of thegas pressure regulator.
 46. The pressure adjusting mechanism of claim42, wherein the pressure adjusting assembly comprises a body tothreadably accommodate a driving member, the rotatable knob being fittedto the driving member so as to threadably rotate and move the drivingmember through the body, wherein the movable spindle defines a pair ofelongate recesses on the outside surface of the spindle, with a pair ofguide pins being fitted within the body to slidingly accommodate andguide the spindle as it moves relative to the body.
 47. The pressureadjusting mechanism of claim 46, wherein the driving member includes acentral enlarged portion that is threaded to match the threading of thebody and a terminal narrowed portion that is threaded to enable it to bethreadably accommodated within the movable spindle, the movable spindlecomprising a sleeve to define an internal thread to match the threadingprovided on the terminal narrowed portion of the driving member, thecentral enlarged portion defining an internal circular recess toaccommodate the movable spindle as the spindle threadably rotatesrelative to the driving member.